1. Field of the Invention
The field of the present invention is processes for producing a high strength structural member and particularly, is improvements of processes for producing such a structural member through a sintering (including a molding and a solidification) of a starting powder material.
2. Description of the Prior Art
In a conventional producing process of the type described above, various starting powder materials have been used. When it is intended to provide a further increased strength of a structural member, it is supposed to use, as a starting powder material, an amorphous single-phase alloy powder or a mixed-phase alloy powder containing amorphous phases and crystalline phases.
The reason is that if a thermal hysteresis of at least a crystallization temperature Tx is applied to the alloy powder, a fine crystal structure uniformly appears notwithstanding it is a high alloy, and therefore, increases in strength and toughness can be expected in the above-described structural member.
However, there is a problem that such alloy powder generates a large amount of heat by an exothermic phenomenon when the amorphous phases are crystallized, and it is actually impossible to control the temperature thereof. This tends to bring about a partial coalescence and a non-homogenization of the crystal structure, making it difficult to provide a structural member of the above-described type having an expected strength.